Heat the oil over medium high heat in a large saucepan. Cook the onion and carrots until onions are fragrant.
Add in the garlic, ginger, curry powder, cinnamon and cumin, and cook for around 2 minutes.
Mix in the tomato paste. Add in the broth, water, coconut milk and lentils, and bring to a boil. Reduce heat and allow to simmer for around 25 minutes, or until the lentils are tender.
Mix in the spinach, lemon juice and salt and pepper to taste. Mix until the spinach is wilted. Serve immediately.